The most recent article on realclimate.org by Michael Oppenheimer argues that we don't really know how fast the Greenland and WA ice sheets might fail. The article goes on to argue that therefore policy should be based on far more pessimistic scenarios than are typically used. I don't know enough glaciology to have an opinion on whether abrupt failure of the ice sheets is plausible.
http://www.realclimate.org/index.php/archives/2006/06/ice-sheets-and-sea-level-rise-model-failure-is-the-key-issue/ I agree with the reasoning behind Oppenheimer's assessment that our policy should be largely driven by the more pessimistic scenarios, though. This is simply conventional risk analysis. A ten per cent chance of a hurricane carries more weight than a ten per cent chance of sunny and warm with occasional light showers in rational planning. Skeptics often claim that if one is uncertain one should act as if the chances of a problem are non-existent. This argument is inane, but they manage to dress it up enough for people to take it seriously. (See for instance the recent discussion about Lindzen's conclusion that since aerosol forcing is poorly known we should treat it as zero watts.) The best strategy, as any decent poker player will patiently explain, is likelihood weighted by cost/benefit. Unfortunately, I don't think we have good formal ways of evaluating either likelihood or cost, but something like a "would not be totally surprised by a 5 meter sea level rise in this century" really ought to count for something. I also think "almost certain of a ten meter sea level rise in this millenium" ought to count for something too, but that's another conversation entirely. mt --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/globalchange -~----------~----~----~----~------~----~------~--~---
